Steam Engine Build: Making the Piston Rod
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- Опубліковано 23 січ 2017
- In this video, I make the piston rod. The piston rod is required because we need to be able to seal the bottom of the cylinder (as well as the top) because a steam engine is double acting.
I am 77 year old Brit, trained as a jig and tool maker but also a keen model engineer since I was 12 years old. I have constructed 6 passenger hauling locomotives, 2 x3.5, 2x 5 & 2x 7.25 inch gauges. On piston rods in the smaller sizes ground stainless is best but for bigger engines a very good material is the shaft from defunct hydraulic rams but not ones that are bent. Find some that are the size closest to the size you need, do not turn them down as they are heavily plated ground and very accurate.
Won’t be tight once it beds in and with proper steam oil, good job
Happy to see you have a lot of videos on file. I know what I will be watching for awhile. Great job and keep up the great work.
Thanks!
Another awesome video!
Do not stop. good luck and high temperatures))
No plans on stopping any time soon! :D
I just got to the end of your videos, and i want more! This is awesome. Building your own engine from design to finish machining is epic, i can't wait to see it "chooch" as they say. Did you have any power/RPM goals when you were designing it?
Thanks for watching! Always nice when people enjoy my videos :D
I wrote up some Matlab code to try an calculate the power I can expect to get, and I am getting about 5.2 ft-lbs max torque and 1 HP (max) at 1000 RPM at 95% cutoff (I have no idea how fast I will be able to spin this engine, but 1000 RPM is a good guess for a steam engine, they run slow). These numbers are right along the lines of something you would expect for an engine of this size. But who knows!
Could be your ways are worn/ twisted too. I could detect no movement when the dead center hit the drilled center in the rod. That means the rod was misaligned with the ways without the tail stock and perhaps the tailstock is misaligned to match. But what do
i know? You are there with the machinery and I am here making guesses, LOL. Is the headstock misaligned with ways? Some H/S have adjustments.
Why use cast iron for the piston rod? most of the time its made of stainless steel, or drill rod, or at least mild steel, just wondering. I hope to build a steam engine soon, I like your videos
Stainless steel would work, but its expensive and hard to machine. I am doing this project on the cheap. Any other kind of steel, especially mild steel would not be ideal because of corrosion issues caused by the condensate. Cast iron has very good corrosion resistance compared to steel. Anyone who has seen an old machine that has sat in the elements knows this all too well. Typically, most of the cast iron parts are perfectly fine, they just have a (relatively) thin layer of corrosion on them. The steel parts are usually pitted like crazy and degraded so much that they need to be replaced. Also, I had extra cast iron around the shop, and that goes back to point 1, building on the cheap. :D
sorry for my English. how many liters of oil is required to melt 1 kg of iron?
That is a tough one to answer. All I know is, when I do a cast iron pour, I use about 3 gallons of oil. Sometimes a little more (when I have a bigger melt) and sometimes a little less (when I have a smaller melt). So lets say an average melt has around 8.5 lbs of iron. Then just as a very rough calculation, it would take roughly 3 liters of oil to melt 1 kg.
was the problem with the taper not just the tailstock being a little out of adjustment. just set too far away from you?
im tyring to learn all this stuff myself but thaught i had seen a tip about that taper situation
That tail stock is always giving me problems, so it definitely could be a contributor to the taper. The lathe is really old too, so wear in the ways also can cause taper.
The taper you get is probably because the lathe is slightly twisted.
Check out this video where a guy removes a taper just like the one you're getting; ua-cam.com/video/lMf-8XSJsE0/v-deo.htmlm38s
I definitely think that is contributing, I have been meaning to level the lathe, but I just keep putting it on the back burner. The main reason, at least I think, is because my tail stock on this lathe is NOT perfectly centered on the axis of the spindle. So when I put the center in the work to support it, the work slightly bends to the side, thus creating the taper.
The reason why I say that I think this is the cause, is because when I don't have the work supported in the tailstock with a center, I hardly get any taper.
If you say so. :)
Another thing I thought about is that you have quite a bit of stickout when you are center drilling. It shouldn't matter much as long as you are supporting it with the tailstock and skimming the entire length though.
Oh, and in every other video on thread cutting I've seen they make the relief cut before cutting the thread. Do you think it is better to do it afterwards?
Nah, I just always forgot to cut the relief and overtime just developed that habit due to my forgetfulness :)
steam engine pistons dont fit that tight ..10 to 15 thousands..piston shouldnt touch the bore
Efficiency 😽😻